Steel TIPS

06.2002 > Use of Deep Columns In Special Steel Moment Frames

By By Jie-Hua Jay Shen, Abolhassan Astaneh-Asl and David B. McCallen

Use of Deep Columns In Special Steel Moment Frames

This report discusses some of the issues related to the use of ědeep columnsî in special moment frames.
Since 1994 Northridge earthquake significant amount of research and development projects have been done
in U.S., Japan and elsewhere on seismic behavior and design of steel moment frames. In almost all of these
research projects, the column used in testing or analyses have been W14 or smaller sections. One of the
most important research projects during this period was the SAC Steel joint Venture Project where a large
number of moment connections were tested and analyzed and design recommendations were formulated. In
this project, almost all specimens had a column with depth of no more than 14-16 inches. However, since in
many cases of moment frames, the governing design requirement is the stiffness to control the drift, the use
of deep columns with a depth of 24, 27 and even 30 inches, becomes very economical. Unfortunately, there
is no extensive and reliable information on actual cyclic behavior and design of moment frames with deep
columns. This report discusses: (a) the issues that need to be considered in using deep columns in moment
frames, (b) a comparison of seismic behavior of two 10 story moment frames designed using W14 and
W27 respectively, (c) the results of a series of realistic non-linear finite element analysis of momentrotation
behavior of connections with deep columns and; (d) the conclusions.